I think that CryptoPing is the most popular signaling service out there so maybe It's worth looking at it. It supports multiple exchanges and also multiple platforms to send you the signals (Slack, Telegram, Discord etc.)

I used it back before their ICO and It wasn't that bad, It simply wasn't for me because I had to deposit money into multiple exchanges and wait for confirmation etc. so you have to be ready at all times If you want to make a profit but apparently, they've improved since then.